Spanning a versatile wide-angle range, the EF 17-40mm f/4L USM Lens is a Canon L-series zoom featuring a constant f/4 maximum aperture along with a sophisticated optical design and durable construction. One Super UD element is featured, along with three aspherical elements, which help to reduce both chromatic and spherical aberrations in order to realize high sharpness, clarity, and color accuracy. A Super Spectra coating has also been applied to suppress flare and ghosting for improved contrast in difficult lighting conditions. Complementing the imaging capabilities, this wide-angle zoom also features a ring-type USM and internal focusing mechanism to afford quick, quiet, and accurate autofocus performance, as well as full-time manual focus override. Additionally, this lens is weather-sealed for use in trying environmental conditions.

EF-Mount Lens/Full-Frame Format    Aperture Range: f/4 to f/22    One Super Ultra-Low Dispersion Element    Three Aspherical Element    Super Spectra Coating    Ring-Type Ultrasonic Motor AF System    Weather-Sealed Construction    Rounded 7-Blade Diaphragm

Wide-angle zoom is designed for full-frame Canon EF-mount DSLRs, however can also be used with APS-C models where it provides a 27.2-64mm equivalent focal length range.

Constant f/4 maximum aperture maintains consistent illumination throughout the zoom range.

One Super Ultra-Low Dispersion glass element noticeably reduces color fringing and chromatic aberrations for high clarity and color fidelity.

Three aspherical elements minimize spherical aberrations and distortions for improved sharpness and accurate rendering.

Super Spectra coating has been applied to individual elements to minimize ghosting and flare for greater contrast and color neutrality when working in strong lighting conditions.

A ring-type Ultrasonic Motor (USM), along with an internal focusing system, is employed to deliver fast, precise, and quiet autofocus performance as well as full-time manual focus override.

Rounded seven-blade diaphragm contributes to a pleasing out of focus quality that benefits the use of shallow depth of field and selective focus techniques.

As a member of the esteemed L-series, this lens is sealed against dust and moisture for working in inclement environmental conditions.

In addition to the front 77mm filter ring, this lens also has a rear filter holder for up to three cut gel filters.

Related Questions and Answers

Q: 1. Is this a good zoom lens for a Canon Rebel t5i camera shooting in limited light like an auditorium or in a movie theater without a flash where the lights have been dimmed?

A: I would recommend purchasing the brightest lens possible for your stated usage needs. Of the options we carry with a similar focal length and compatible for use on the Canon EOS Digital Rebel T5 DSLR camera, I would recommend the Sigma 18-35mm f/1.8 DC HSM Art Lens for Canon EF, B&H # SI183518DCC, for your usage needs. The constant f/1.8 aperture is 2.3 f-stops brighter than the f/4 aperture used on the Canon EF 17-40mm f/4L USM Lens. As an example, if your shooting conditions require you to have an exposure of f/4 at 1/13 sec. to get a properly exposed image, and there is a chance you can get blurred images due to a slow shutter speed, the Sigma lens would give you the ability to shoot an equivalent exposure of f/1.8 at 1/60 sec., which is much faster to hand-hold this lens at any of its focal lengths with minimum blur from hand movement. You may further use a higher ISO setting to assist in obtaining an exposure with a shutter speed fast enough for your specific lighting conditions. However, do note that the lighting conditions you list above are extreme, so you may need a higher-than-normal ISO setting, and which is why the brighter Sigma 18-35mm f/1.8 DC HSM Art Lens for Canon EF would be a better option for your indicated usage needs.

Q: 2. Has anyone used this lens on a crop sensor like the 80D for video and if so how did you like the results?

A: Hi, I have bought this lens originally for my 7D, and it works great as a walk around lens. Due to the cropped sensor, it behaves more like a 24-70mm on a full-frame. For video, I have shot several travel videos and product videos with the lens. Picture quality and color is top-notch. The zoom is smooth. In my opinion, having a cropped sensor on this lens is better for video, as it crops out the edges where lines are distorted. Hope this helps.

Q: 3. Can this be used with Canon Rebel

A: Yes it can be used with Canon Rebel models (film and digital). The Canon 17-40mm f4 USM L series lens is compatible with all Canon EOS cameras (film and digital).

Q: 4. Is this lens parfocal?

A: Yes, the 17-40 is considered a Parfocal lens. And note that Parfocal zooms in the Canon EF lens line-up are essentially limited to the fixed-aperture L-series category and front-focusing zoom lenses.

Q: 5. Is using this lens with a speedbooster on an APS-C camera will effectively convert the focal length to 12-28mm with an aperture of one stop faster?

A: Yes, but you still need to apply the APS-C crop factor to the "12-28mm f/2.8" that you're getting via the Speedbooster.

Q: 6. i want to combine this lense with the sony a6000 with sigma mc 11 adapter . or should i just get the sony 10 18 mm . thanks

A: Generally native lenses work more smoothly than non-native lenses with adapters. Also best in mind that the a6000 is an APS-C camera so the 17-40 will become a 27-64mm equivalent lens on the a6000 (give or take a few mm, depends on exact APS-C sensor size)TL;DR 10-18

Q: 7. will this lens work with large family groups?

A: Yes, a Canon EF 17-40mm f/4L USM Lens can work for shooting large family portraits.

Q: 8. How is this lens compared to the Canon EF 16-35mm f/4L IS USM Lens? Also considering that it is cheaper?

A: It is older, but still a very good option for a wide angle zoom. It is also lighter and smaller too.

Q: 9. Can it be use on Canon EOS R5 ?

A: A Canon Mount Adapter EF-EOS R, BH # CAMAEFRF will allow this EF 17-40mm f/4L USM Lens to function with the Canon EOS R5. https://bhpho.to/300yC91

Q: 10. Can I use the EF 17-40 f/4L on my 5D SR (with tripod) for Astrophotography?

A: The Canon EF 17-40mm f/4L USM Lens is fully compatible with the Canon EOS 5DS R. This is a good wide angle lens option for astrophotography.